Abu Dulaf Mosque is a historic mosque located north of Samarra in the Saladin Governorate, Iraq. The mosque was commissioned by the 10th Abbasid Caliph Al-Mutawakkil in 859. The mosque is rectangular shaped, and consisted of the open air sahn surrounded by the corridors with the qibla corridor being the biggest of them. The mosque is among the largest mosques in the world measured by area size, reaching 504,000 square feet wide. The iconic spiral minaret which resembles the renowned Malwiya of the Great Mosque of Samarra is located at the northern side. The unique design of the minaret is said to be inspired by the similar structure in Firuzabad. The minaret reaches 105 feet and standing on a square base Abbasid architecture developed in the Abbasid Caliphate between 750 and 945, primarily in its heartland of Mesopotamia. The Abbasids inherited Persian architectural traditions in Mesopotamia, and were later influenced by Central Asian styles. They evolved distinctive styles of their own, particularly in decoration of their buildings. While the Abbasids lost control of large parts of their empire after 850, their architecture continued to be copied by successor states in Iran, Egypt and North Africa. No photographer credited, undated.